Displays in image display devices, such as television devices, are now being shifted from conventional cathode-ray tube displays to thin display panels, such as liquid crystal panels and plasma display panels. With the thin display panels, the thicknesses of the image display devices can be reduced. Liquid crystal panels included in liquid crystal display devices do not emit light, and thus backlight devices are required as separate lighting devices. The backlight devices are classified broadly into an edge-light type and a backlight type according to mechanisms. Edge-light type backlight devices are preferable for further reducing the thickness of liquid crystal display devices. An example of edge-light type backlight devices is disclosed in Patent Document 1.
In Patent Document 1, an LED board on which LEDs are mounted are arranged opposite an end surface of a light guide plate and the LED board is attached to a heat dissipation member. The LEDs are light sources. Heat from the LEDs is transmitted to the heat dissipation member via the LED board. This configuration is for promoting heat dissipation.